/* Website design */
:root {
  --color-primary:        #1a56a8;   /* buttons, headings */
  --color-primary-dark:   #123d80;   /* hover states */
  --color-primary-light:  #e8f0fb;   /* result boxes, tags */
  --color-accent:         #2f7dd4;   /* header gradient end */
  --color-bg:             #f0f4fb;   /* page background */
  --color-card:           #ffffff;
  --color-border:         #bdd0ee;   /* border */
  --color-text:           #0f2042;   /* text */
  --color-text-muted:     #5070a0;   /* muted text */
  --color-warn-bg:        #fff3f2;
  --color-warn-text:      #b83232;
  --color-warn-border:    #f5c6c2;
  --color-amber:          #c98a1a;
  --color-amber-bg:       #fffbf0;
  --color-disclaimer:     #3a6fc4;   /* disclaimer accent */
  --color-disclaimer-bg:  #edf2fc;   /* disclaimer background */
  --radius-card:          14px;
  --radius-input:         8px;
  --shadow-card:          0 2px 18px rgba(0, 50, 35, 0.08);
}

/* Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* Base */
body {
  font-family: Calibri, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.65;
}

/* Language Toggle Bar */
.lang-bar {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 10px 20px;
  background: var(--color-card);
  border-bottom: 1px solid var(--color-border);
}

#langToggleBtn {
  background: var(--color-primary);
  color: #fff;
  border: none;
  padding: 7px 20px;
  border-radius: 20px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 0.03em;
  font-family: inherit;
  transition: background 0.18s, transform 0.1s;
}

#langToggleBtn:hover  { background: var(--color-primary-dark); }
#langToggleBtn:active { transform: scale(0.97); }

/* Header */
.app-header {
  text-align: center;
  padding: 40px 24px 32px;
  background: linear-gradient(140deg, var(--color-primary-dark) 0%, var(--color-accent) 100%);
  color: #fff;
}

.app-title {
  font-size: clamp(1.7rem, 5vw, 2.6rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  margin-bottom: 10px;
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.18);
}

.app-slogan {
  font-size: clamp(0.88rem, 2.2vw, 1.1rem);
  opacity: 0.88;
  font-weight: 400;
  letter-spacing: 0.04em;
}

/* Page Container */
.container {
  max-width: 740px;
  margin: 0 auto;
  padding: 28px 16px 60px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Cards */
.card {
  background: var(--color-card);
  border-radius: var(--radius-card);
  padding: 28px;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--color-border);
}

/* Form Groups */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.92rem;
  margin-bottom: 7px;
  color: var(--color-text);
}

.form-group select,
.form-group input[type="number"] {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-input);
  font-size: 0.96rem;
  color: var(--color-text);
  background: var(--color-card);
  font-family: inherit;
  appearance: auto;
  transition: border-color 0.18s, box-shadow 0.18s;
}

.form-group select:focus,
.form-group input[type="number"]:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26, 107, 90, 0.14);
}

/* Validation Message */
.validation-msg {
  background: var(--color-warn-bg);
  border: 1px solid var(--color-warn-border);
  color: var(--color-warn-text);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 0.88rem;
  margin-bottom: 16px;
  display: none;
}

.validation-msg.visible {
  display: block;
}

/* Buttons */
.btn-group {
  display: flex;
  gap: 12px;
  margin-top: 8px;
}

.btn-primary {
  flex: 1;
  padding: 13px 20px;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-input);
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.18s, transform 0.1s;
}

.btn-primary:hover  { background: var(--color-primary-dark); }
.btn-primary:active { transform: scale(0.98); }

.btn-secondary {
  padding: 13px 22px;
  background: var(--color-card);
  color: var(--color-text-muted);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-input);
  font-size: 1rem;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.18s;
}

.btn-secondary:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* Results */
.results-card {
  border-left: 4px solid var(--color-primary);
}

.results-card h2 {
  font-size: 1.15rem;
  color: var(--color-primary);
  margin-bottom: 14px;
}

/* fish name / mercury / standard / weight */
.results-info-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.info-tag {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border: 1px solid rgba(26, 107, 90, 0.2);
  border-radius: 20px;
  padding: 4px 12px;
  font-size: 0.8rem;
  font-weight: 500;
  white-space: nowrap;
}

/* Results Grid */
.results-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 16px;
}

@media (max-width: 500px) {
  .results-grid { grid-template-columns: 1fr; }
}

.result-box {
  background: var(--color-primary-light);
  border-radius: 10px;
  padding: 18px 16px;
  border: 1px solid rgba(26, 107, 90, 0.18);
}

.result-box-title {
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-text-muted);
  margin-bottom: 10px;
}

.result-primary {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.15;
  margin-bottom: 6px;
}

.result-primary span.unit {
  font-size: 1.1rem;
  font-weight: 500;
}

.result-secondary {
  font-size: 0.83rem;
  color: var(--color-text-muted);
  line-height: 1.9;
}

/* Estimate footnote inside results */
.estimate-note {
  font-size: 0.81rem;
  color: var(--color-text-muted);
  font-style: italic;
  padding-top: 14px;
  border-top: 1px solid var(--color-border);
  line-height: 1.65;
}

/* Section Titles */
.section-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 12px;
}

/* Formula */
.formula-content {
  font-size: 0.875rem;
  color: var(--color-text);
  line-height: 1.85;
}

.formula-content h4 {
  font-size: 0.88rem;
  color: var(--color-text);
  font-weight: 700;
  margin-top: 14px;
  margin-bottom: 5px;
}

.formula-content h4:first-child {
  margin-top: 0;
}

.formula-content ul {
  padding-left: 20px;
}

.formula-content li {
  margin-bottom: 3px;
}

.formula-content code {
  background: var(--color-primary-light);
  color: var(--color-primary);
  padding: 1px 6px;
  border-radius: 4px;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.85em;
}

/* Disclaimer */
.disclaimer-card {
  border-left: 4px solid var(--color-disclaimer);
  background: var(--color-disclaimer-bg);
}

.disclaimer-card .section-title {
  color: var(--color-disclaimer);
}

.text-muted {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

@media (max-width: 600px) {
  .card { padding: 20px 16px; }
  .btn-group { flex-direction: column; }
  .btn-secondary { text-align: center; }
}